Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
cham duc » pham duc, cham soc, pham duy
ban hanh » ban hang
tu sach » thu sach, te sach, tu cach
hieu vu » hieu va, hieu ve, hieu su
vu cham » va cham, vu kham, tu cham
nang ma » tang ma, sang ma, nang cao
su sach » so sach, vu sach
su viet » so viet
v nang » va nang, vu nang, van nang

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) OR (su sach)) v nang ma hoa. hieu vu cham duc ((van thanh) or (ban hanh)) va su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) v nang ma hoa. hieu vu cham duc ((van thanh) OR (ban hanh)) va su viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) v nang ma hoa. hieu vu cham duc ((van thanh) or (ban hanh)) va su viet*".